John doyle



(No Model.)

J. DOYLE.

RHEOSTAT.

No. 321,285. Patent-ed June 30, 1885.

N. PETERS, PhmwLilhognpher. wnhinglun. D. C.

, UNITED STATES PATENT OFFICE.

JOHN DOYLE, OF HOBOKEN, NEV JERSEY, ASSIGNOR TO HIMSELF AND C.

GOLES DUSENBURY, OF N EV YORK, IT. Y.

RH'EOSTAT.

SPECIFICATION forming part of`Letters Patent No. 321,285, dated June 30,1885. Application filed December 10, 1884. (No model.)

To all Lwhom, t may concern:

Be it known that I, JOHN DOYLE, of Hoboken, in the county of Hudson and State ofNew Jersey, have invented an Improvement. in Rheostats, of which the following is a specification.

In Letters Patent No. 298,073,granted May 6, 1884, a rheostat is described, in which a number of small plates are placed in a nonconducting holder and pressure applied to bring the surfaces into contact, and in my application No. 126,116, filed March 3l, 1884, a rheostat is represented in a circular form with a movable contact or switch.

My present invention relates to a rheostat in which the resistances are placed in a circular range and connected up in such a manner that the movement of a rotating switch or circuitcloser adds resistances successively and ultimately entirely breaks the circuit; or when turned the other way the resistances are cut out one after the other until the current is free from the resistances ofthe rheostat. In all cases the spark is lessened or prevented by the action of the resistances, and the instrument is within a nonconducting and rire-proof case, so that injury cannot arise from Contact with the case, or from any heat generated by the resistance.

This rheostat is especiallyadapted to electric lamps, and can be used for varying the intensity of the same and for turning them fully on or off.

In the drawings, Figure lis an elevation of the rheostat, with the case in section. Fig. 2 is a view of the head and circuit-closing pins. Fig. 3 is a section of the rheostat longitudinally in enlarged size; and Fig. 4 is a crosssection at the line :v

The rheostat is made with having a handle or pointer, b, at one end, by means of which the central shaft can be rotated, and with it the circuit-closerc, and there is a circular range of contact-st'uds,e,in a head, f, of insulating material, over which studs e a central shaft, a,

the closer c ismoved. This closer c is wide enough to rest upon two studs, so as to make contact with the second before separating from the first, and thereby the -sparks is prevented.

There is a second head, g, of insulating madevelop ment of terial, between lwhich and the head f there is a circular range of rcsistances, and the heads f and g are connected by a central column, 71., through which the shaft c passes.

There is ahead, 7c, preferably of asbestus paper, and a case, m, of similar material, surrounding the rheostat, and this casein is preferably-perforated, so as to allow atmospheric air to circulate through the same, and this c'a-se is usually ornamented with a vitrilied surface and with metal rims 2 2 to connect the cylindrical portion to the heads.

One wire,3, is attached to the central shaft, a, by being wound around the same between the collars o o. One collar is fixed on the shaft, and the spring 5 presses the other collar against the wire to insure electric contact. The circuit-wire 3 may be received at the binding post or stud -l-. 4The other circuit-wire, 6, is connected to the head or case and passes to the stud 7, so that when the circuit-closer cis in contact with 7 the current passes from Jr through 3, shaft a, to closer c, thence by 7 and wire 6 to lamp or other working device.

The wires t" pass in succession from one of the studs c in the circular range of contactstuds to one end of one resistance and to the other end of the next resistance all the way around the circular` range of resistances, as seen in Fig. l, so that these resistanccs are added in succession into the circuit by turning the closer around and moving it away from the stud 7, and when the closer has been moved around the circular range it passes off thelast stud in the electric circuit upon an insulated stud, a, and the circuitv is thereby broken. There will be little or no spark,becauSe the resistances check the current before the circuit is broken. The screws or pins 9 l0 form stops to the movement of the circuit-closer.

Each resistance is made with the metallic end pieces, i and q, and intermediate inferior conductor. I prefer to employ the tube s, .of porcelain or similar material, with the disks of German silver, u, or equivalent material, within such tube and between the end pieces, 'i q, and in order to apply a pressure to the pieces u, I apply a spring around the end piece, fi, abutting against a cross pin or collar upon z' and resting at the other end against the head g.

In place of disks of German silver to form ICO the resistance, plumbago or a Composition of plumbago and borax, as in my said application7 or any other suitable material, may be made use of.

The range of resistances may contain any desired number, each being made as aforesaid, and although it is most convenient to place such resistances in a circular range, I do not limit myself in this particular.

rlhe pressure endwise upon the .rods or bars may be obtained by screws, instead ot' the springs.

I do not claim a holder for pieces or plates of carbon and a turning-key and presser for :ausing the more or less intimate Contact of the pieces of carbon.

I do not claim a range ol' carbon plates and screws or springs to compress them more orless.

I claim as my inventionl. The combination, with the central sliaft, u, and circuit-closer, ofthe headsf and g and connecting column 71,7 the range of resistanees around the central column, the circular range of contact-pins, and the circuit-connections, substantially as set forth.

2. The combination, in a rheostat,of a range of resistances, each of which is composed ol' metallic pieces of inferior conductivity, nonconducting holders for the same, circuit-Wires for connecting` the resistanees in series, oontact-pins, and a movable switch Vi'or bringing into the electric circuit more or less ofthey resistanees, substantially as speci lied.

3. The combination, with the case m and heads f and g, of the connection between the heads, tbe range of resistanees supported by the heads f and g, the shaft a, extending from the head g to the head h, and a circuit-closer and handle7 substantially as set forth.

Signed by me this Lth Clay of December, A. D. 1884.

.TOI-IN DOYLE.

\Vitnesses:

GEO, T. PINCKNEY, WLLLIAM G. Mo'r'r. 

